<div id="footer">
    <?php require 'social.php'; ?>
    <?php $pageName = basename($_SERVER['PHP_SELF']); ?>
    <ul>
        <li><a <?php if ($pageName == "returns.php") {
                echo 'class="current"';
            } ?> href="returns.php">Shipping & Returns</a></li>
        <li><a <?php if ($pageName == "contactus.php") {
                echo 'class="current"';
            } ?> href="contactus.php">Contact</a></li>
        <li><a <?php if ($pageName == "about.php") {
                echo 'class="current"';
            } ?> href="about.php">About Us</a></li>
    </ul>
</div>